Search found 1033 matches

by bussieck
4 months ago
Forum: Syntax
Topic: Option Threads = 8
Replies: 4
Views: 10772

Re: Option Threads = 8

Where did you read about "option threads=n"? Probably in a much newer GAMS documentation. Software evolves. Your version of GAMS is 13 years old! If you use that old software use the documentation that came with that version. At that time, there was no general GAMS option "threads&quo...
by bussieck
5 months ago
Forum: Announcements
Topic: GAMS Distribution 45.1.0 (Major Release)
Replies: 0
Views: 22026

GAMS Distribution 45.1.0 (Major Release)

Hi GAMS Users,

We started distributing GAMS Release 45.1.0 on October 17, 2023.

You can download the software from https://www.gams.com/download/

Here are the release notes: https://www.gams.com/latest/docs/RN_45.html

Your GAMS Team
www.gams.com
by bussieck
5 months ago
Forum: Announcements
Topic: GAMS Distribution 45.0.0 (Beta Release)
Replies: 0
Views: 20026

GAMS Distribution 45.0.0 (Beta Release)

Hi GAMS Users, We would like to announce the availability of the GAMS Beta Release 45.0.0. Please consult the beta release notes for details about new features and updated solvers: https://www.gams.com/beta/docs/RN_45.html If you are interested in experimenting with this beta release, please downloa...
by bussieck
6 months ago
Forum: Modeling
Topic: define new equation in each loop iteration
Replies: 3
Views: 9427

Re: define new equation in each loop iteration

There is a somewhat simpler example: cta (https://www.gams.com/latest/gamslib_ml/ ... b_cta.html) which essentially cuts away the optimal solution a couple of time to get suboptimal solutions. -Michael
by bussieck
6 months ago
Forum: Modeling
Topic: define new equation in each loop iteration
Replies: 3
Views: 9427

Re: define new equation in each loop iteration

Look at a TSP example (https://www.gams.com/latest/gamslib_ml/ ... _tsp1.html) in the GAMS model library where a sub-tour elimination constraint gets added in every iteration. You will need to overestimate the number of iterations (cc) and use a loop though. Good luck.

-Michael
by bussieck
6 months ago
Forum: Solvers
Topic: Baron License error
Replies: 1
Views: 6258

Re: Baron License error

The error message is slightly misleading, it probably failed because the model you want to solve is too big for the community license. See https://www.gams.com/latest/docs/UG_License.html#UG_License_Additional_Solver_Limits for the model size limits for the community license. BARON has tighter limit...
by bussieck
6 months ago
Forum: Syntax
Topic: Assistance Needed with Correcting Dimension and Operand Errors in Lines 97-101
Replies: 1
Views: 5903

Re: Assistance Needed with Correcting Dimension and Operand Errors in Lines 97-101

The listing file points you nicely to the issue and gives a reasonable explanation "Incompatible operands for relational operator": 95 inventoryBalance(p,s,t).. 96 I(t,p,s) =e= I(t-1,p,s) + X(t,p,s) - sum(s_1$(s_1 = sPrec(p,s) and s_1<>s), X(t-rt(s,s_1),p,s_1)*a(p,s)) - d(t,p,s); **** $148...
by bussieck
6 months ago
Forum: API
Topic: Python API ignores default Solver?
Replies: 4
Views: 5556

Re: Python API ignores default Solver?

The optgams.def file is a file to let e.g. Studio know what options GAMS accepts and what their default values are. The GAMS documentation never had anything on adjusting the file. It is for pure internal use and editing might have some unexpected results.

-Michael
by bussieck
6 months ago
Forum: Syntax
Topic: the uncertain wrong of minimizing
Replies: 6
Views: 9700

Re: the uncertain wrong of minimizing

Why do you expect the ratio to be stable? Many optimization problems are degenerate, i.e. with the same objective function you have many solutions. Which one the solver spits out is a matter of chance. So if you change the input (e.g. different bounds) the solver takes a slightly different path and ...
by bussieck
6 months ago
Forum: Modeling
Topic: Model Inquiry
Replies: 1
Views: 6291

Re: Model Inquiry

The solver tells you the model is infeasible. There are many tools to analyze infeasibility. Infeasibility is a normal state for a mathematical program (besides optimal and unbounded). There are tools (e.g. iis or feasopt) that help you pinpoint the cause for the infeasibility. Search the forum for ...